Release coating for silicone pressure sensitive adhesives

ABSTRACT

A laminate comprising a substrate, a continuous layer of a release coating on one surface thereof, and a layer of a silicone pressure sensitive adhesive on the surface of said release coating, said release coating being a mixture of a resin having perfluoro side chains and a film forming resin which binds said resin having said perfluoro side chains to said substrate, wherein said film forming resin is selected from the group consisting of polyester, polyamides, functionalized polyolefins, and nitrile polymers and copolymers.

This is a continuation of application Ser. No. 08/100,103 filed Jul. 30,1993, now U.S. Pat. No. 5,451,440.

BACKGROUND OF THE INVENTION

The present invention relates generally to the release of siliconepressure sensitive adhesives, herein called SPSAs. In a particularaspect, this invention relates to curable coating compositions and toarticles of manufacturing comprising the cured coatings.

SPSAs, such as those disclosed in U.S. Pat. Nos. 2,736,721; 2,814,601;2,857,356; 3,528,940; 3,929,704; 3,983,298; 4,309,520; Canadian PatentNo. 711,756 and British Patent No. 998,232 are well known for theirexcellent thermal stability and tenacious adhesiveness. While theseproperties are valuable, the adhesiveness, e.g., tack and/or adhesivestrength, of SPSAs presents a significant problem. Whether the SPSA isin the form of roll of tape, an adhesive layer on an article protectedwith a peelable backing, or a transfer adhesive layer protected on twosurfaces by peelable backings, the SPSA must be separated from anadjacent surface provided with a release layer before it can be used forits intended purpose. Because of its tenacious adhesiveness speciallydesigned release coatings are required for SPSA's.

Conventional release films which have been used with organic pressuresensitive adhesives (OPSAs) are generally unsuitable for use with SPSAsfor a number of reasons. They may provide too tight release, i.e., toomuch force (the release force) may be required to remove the adhesivecoated substrate from the release surface and in an extreme case theadhesive coated substrate may tear; they may not be sufficientlycohesive, e.g., the release coat may be displaced by the adhesive andtransfer to the adhesive surface thereby reducing adhesiveeffectiveness; or when the SPSA is cast directly on the release backingthe release film may provide unacceptably tight release or the SPSA maybe contaminated with the release agent.

One class of release backing which has been found to be suitable for usewith SPSA's employs fluorosilicone polymers. Examples of this type ofbacking are provided in U.S. Pat. Nos. 5,132,366; 4,980,443; 4,968,766;4,889,753; 4,842,902; 4,736,048. This system has been found to sufferfrom several drawbacks which limit its usefulness. There is often a needto adjust the release properties of a backing and it is very difficultto do this using the fluorosilicone system because the perfluoro monomeris reacted into the fluorosilicone polymer off-site. Thus, the systemhas a fixed fluorine content which determines the release force and itis difficult to control the release properties of the coating andthereby tailor its release properties to the particular needs of theparticular adhesive system with which the polymer is used. In addition,the fluorosilicone polymers are comparatively expensive which makes therelease coating undesirable for use on paper or highly textured orabsorbent substrates. From a practical standpoint, this limits theeconomic usefulness of the coating to application to films.

Release coatings which contain polymers including perfluoro groups areknown in the art. For example, U.S. Pat. No. 4,523,059 to Dabroskidiscloses aqueous release coating compositions containing polymersderived from perfluoroalkylalkyl acrylates. U.S. Pat. No. 4,873,140 toMcintyre discloses a coating of an in situ polymerizedpoly(perfluoropropylenoxy) acrylate or methacrylate. U.S. Pat. No.4,472,480 to Olson discloses a perfluoropolyether release coating. U.S.Pat. No. 3,536,749 to Grones discloses an acrylate adduct of afluorocarbon amide.

U.S. Pat. No. 3,502,497 to Crocker discloses a release coatingcomprising a copolymer of stearyl methacrylate and acrylonitrile, arelease agent, and a film forming composition based upon an alkyd resin.

An improved release backing for pressure sensitive adhesives (PSAs), andparticularly, SPSAs is thus needed in the adhesive industry.

SUMMARY OF THE INVENTION

It is an object of this invention to provide an improved release backingfor SPSAs. It is a more particular object of this invention to providean improved article comprising a layer of SPSA which is protected by apeelable release backing. It is an additional object of this inventionto provide a particularly preferred release coating composition forpreparing a surface that will release a SPSA and which can also be usedin releasing aggressive organic pressure sensitive adhesives (OPSAs).

These objects and others, which will be apparent upon considering thefollowing disclosure and appended claims, are obtained by the presentinvention which, briefly stated, provides a laminate comprising asubstrate, a layer of a release coating on one surface of the substrate,and a layer of a silicone pressure sensitive adhesive on the surface ofthe release coating, the release coating being a mixture of a resinhaving perfluoro side chains and a film forming resin which binds theresin having the perfluoro side chains to the substrate; and provides acoating composition useful in providing a release coat which comprises aresin having perfluoro side chains, a polyester resin, an aminoplastresin and a curing catalyst. This coating can be used to release OPSAsand SPSAs.

Surprisingly, it has been found that the composition of this inventionsucceeds where compositions of the prior art fail in the release ofSPSAs.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the invention, a resin having perfluoro side chains(hereinafter a "perfluororesin") and a film forming resin are selectedhaving a degree of polymer compatibility which allows the perfluorogroups to concentrate on the surface of the coating while theperfluororesin remains bound to the substrate surface by the film formerresin. The term "perfluoro" as used herein includes perfluoroalkylgroups having 4 to 14 carbon atoms and other perfluoro side chains of 4to 14 carbon atoms known in the art. If the perfluororesin and the filmforming resin are not sufficiently compatible, the composition can notbe coated uniformly without separation, the perfluororesin will befugitive and/or contaminate the adhesive through off set or the like. Ifthey are too compatible, the perfluoro groups will remain dissolved inthe film former and the perflurogroups will not concentrate on thesurface of the coating and reduce surface energy as desired. As anexample of compatibility, when a polyester resin is used as the filmformer, because the polyester resin is relatively polar in character, aperfluororesin with some polar character provides the desiredcompatibility. Preferred perfluororesins for use with polyesters haveperfluoro groups and, more particularly perfluoroalkyl groups as sidechains which extend from a polar resin backbone such as a polyacrylate.

Representative examples of useful perfluororesins are resins havingperfluoro side chains extending from a polymeric backbone and includepolyethers, polyacrylates, polymethacrylates, etc. having perfluoro sidechains, many of which have been described in the literature. See U.S.Pat. Nos. 4,873,140; 4,472,480; and 3,536,749 for examples ofperfluororesins. Useful resins may be derived from any of the ZONYLfluorochemical intermediates available from the DuPont Company includingits fluorotelomers, its fluoroalcohols, its fluoroolefins, itsfluoroalkylacrylates, its fluoroalkylmethacrylates, itsfluoroalkylstearates, its fluoroalkylcitrate, its fluoroalkylthiocyanateand its fluoroalkylsulfonic acid. These intermediates may be reactedwith themselves or co-polymerized with other monomers to provide a mainchain which is compatible with the film forming resin. The comonomer maybe an acrylate or a methacrylate, a nonacrylate ester such as, vinylacetate, or a vinyl monomer. Preferably, the perfluoro resins have afluorine content of about 45 to 70% and more particularly 30 to 50%.

In accordance with the preferred embodiments of the invention, theperfluoropolymer is a perfluorinated ester polymer. These polymers arehomopolymers and copolymers of ω-perfluoroalkylalkyl acrylates. Byω-perfluoroalkylalkyl acrylate is meant a structure which may berepresented as

    R.sub.f --C.sub.n H.sub.2n --OOCR═CH.sub.2

wherein R_(f) represents F[CF₂ ]_(p) and n and p are 4 to 14.Perfluoroalkylalkyl acrylate polymer compositions are availablecommercially as aqueous dispersions which may contain polymerizablemonomers and/or polymerizable or cross-linkable oligomers. Aparticularly suitable fluropolymer composition is commercially availablefrom DuPont under the name ZONYL 7040.

While not desiring to be bound it is believed that upon curing thecoating composition of the present invention an interpenetrating networkof the perfluororesin in the film forming resin is formed which bindsthe perfluororesin to the substrate and prevents its transfer to thePSA. The fluorochemical nature of the perfluoro groups in the resinallows them to extend from the network to provide a surface having lowsurface energy.

The film forming resin used in the present invention must exhibit thecompatibility characteristic with respect to the perfluororesindescribed above. Useful film formers include polyester resins,polyamides, functionalized polyolefins such as functionalizedpolypropylenes and functionalized polyethylenes, nitrile polymers andcopolymers, etc. The preferred film formers are polyester resins.

A variety of polyester resins may be used as film formers in theinvention including polyesters of aromatic dicarboxylic acids oranhydrides such as terephthalic anhydride, phthalic anhydride, etc. Theterm "polyester resin" includes alkyd resins as a preferred embodimentthereof.

Alkyd resins are the condensation product of a polycarboxylic acid, apolyol, and an oil. Polycarboxylic acids such as, for example, oxalicacid, malonic acid, succinic acid, sebacic acid, adipic acid, pimelicacid, suberic acid, azelaic acid, tricarballylic acid, citric acid,tartaric acid, maleic acid, phthalic acid, isophthalic acid,terephthalic acid, itaconic acid, citraconic acid, and mixtures thereofcan, among others, be used in preparing the alkyl resins employed inthis invention. Of course, any of the anhydrides of the aforementionedacids can be used in equivalent amounts in place of the acids. Phthalicacid or anhydride is a preferred constituent of the polycarboxylic acidcomponent.

Typical polyots useful in the alkyd resin are, for example, ethyleneglycol, diethylene glycol, tetramethylene glycol, pinacol, trimethylolpropane, trimethylol ethane, mannitol, sorbitol, glycerol,pentaerythritol and mixtures thereof. Glycerol is a preferred polyol.Coconut oil alkyd resins have been found to be particularly useful. Onecoconut oil alkyd resin which is useful in the invention is DorescoAKN29.1 from Dock Resins, Inc. This resin is a condensation product ofphthalic anhydride, coconut oil fatty acids and glycerine.

Examples of functionalized polyolefins include sulfonated andchlorinated polyolefins such as sulfonated or chlorinated polyethylenesand polypropylenes, malaeic anhydride adducts of sulfonated, chlorinatedpolyolefins, such as DuPont Co. HYPALON polymers, etc.

Examples of nitrile polymers and copolymers include carboxyl terminatedor amine terminated acrylonitrile resins such as Hycar 1300X8, 1300X9,1300X13 from B. F. Goodrich.

The film former is selected based on the thermal stability of thesubstrate or vice versa. Film forming resins requiring elevatedtemperatures for curing will be used with thermally stable substrates.For example, alkyd systems are used with substrates like PET which arestable whereas film formers which are simply dried may be used with lessstable substrates such as polyolefins films.

Depending upon the nature of the film former, it may be necessary ordesirable to include a crosslinking agent in the composition. When usinga polyester or an alkyd resin, the coating composition preferablyincludes an aminoplast resin. Any of the conventional aminoaldehyderesins which are compatible with the other resins in the composition canbe used. Such aminoaldehyde resins are formed by the reaction ofpolyamines such as, for example, melamine and urea with aldehydes suchas formaldehyde, acetaldehyde and furfural. Preferred resins areprepared by reacting urea or melamine with a molar excess offormaldehyde, then etherifying the resulting methylol melamines ormethylol ureas with, for example, methyl, ethyl, propyl or butylalcohol. Butylated urea-formaldehyde and melamine-formaldehyde resinsand partially condensed methoxy methylol melamines are particularlypreferred.

The aforementioned conventional-alkyd resins and amino-aldehyde resinsand mixtures thereof are described in more detail in U.S. Pat. Nos.2,191,957, 2,197,357, and 2,218,474. A particularly preferred resin is abutylated melamine formaldehyde resin such as Doresco BM8-1 commerciallyavailable from Dock Resins, Inc.

Other conventional crosslinking agents can be used to cure the filmformer include phenolics, epoxies, and polyisocyanates. While it ispreferred to use a combination of a coconut oil alkyd and butylatedmelamine formaldehyde, by adjusting the amounts of the resin and thecrosslinker other combinations of resins and crosslinkers may be used inthe invention which provide a combination of cohesive strength andadhesion to substrate useful in the release coatings.

The removal force is dependent upon the ratio of resin (e.g., alkyd) tocrosslinker (e.g., melamine), the level of perfluorinated ester, and thecrosslink density of the coating and can be adjusted as such. The ratioof the polyester or alkyd resin to the aminoplast resin or crosslinkeris a principal factor in determining the cohesive strength of thecoating and its adhesive strength to the substrate surface, i.e., thesurface carrying the release coating. Ordinarily the coating may containfrom about 40 to 90 parts (dry weight) alkyd and 10 to 50 partsaminoplast. Preferably, the coating contains about 65 to 75 parts of thealkyd resin and 10 to 20 parts of the aminoplast resin. With increasingamounts of the aminoplast, the coating tends to become brittle. As theamount of the aminoplast decreases below acceptable levels, the coatingloses strength.

To cure coatings of a polyester or alkyd resin and an aminoplast resin,an acid catalyst may be incorporated into the composition. Those skilledin the art will appreciate that a variety of catalysts may be used forthis purpose. Suitable catalysts include, for example, octyl acidphosphate, amyl acid phosphate, butyl acid phosphate, ortho-phosphoricacid and citric acid. Although the aforementioned catalysts are notessential, they do materially shorten the drying and curing time andhence the processing time, for tapes, labels, and the like made with therelease coating of this invention. Some of the more commonly preferredcatalysts are p-tuluenesulfonic acid, alkyl acid phosphates, etc. Theamount of the catalyst is not particularly critical. A suitable amountis used to provide the desired cure rate and can vary from 0 to 12%.Typically about 0.5 to 3% of catalyst is sufficient.

The tightness of the release or the force required to remove the releasefilm from the PSA layer can be adjusted by adjusting the amount of thefluororesin in the coating. The amount and tightness of release willalso vary with the nature of the fluororesin and the surface characterof the surface upon which the coating is coated. For SPSAs, thefluororesin is generally present-in the coating composition in an amountof about 2 to 10% by weight (dry weight).

While release coatings in accordance with the invention are particularlyuseful because they release SPSAs, those skilled in the art willappreciate that these coatings can also be used with OPSAs which aregenerally less aggressive than SPSAs. For OPSAs somewhat lower amountsof fluororesin may be used, for example, for OPSAs the amount may rangefrom about 0.25 to 5% by weight (dry).

In some cases it may be desirable to reduce the adhesive strength of anadhesive to reduce the release force. One technique that can be used toreduce the release force is to modify the PSA to include small amountsof the fluropolymer. By incorporating controlled amounts of thefluropolymer in the adhesive, the adhesive bond to the release coatingcan be reduced. For example additions of about 0.25% to 2.0% dry weightto the OPSA or SPSA have been found helpful in controlling release.

The coating components can be mixed together and applied directly to asubstrate. If desired a solvent may be added to the composition toenhance coating properties. Any of a wide variety of aliphatic, aromaticand cycloaliphatic hydrocarbons, alcohols, ketones, ethers and esterssuch as, for example, ethyl, propyl, butyl and isobutyl alcohols,xylene, toluene, glycol ethyl ether, glycol monacetate, diacetonealcohol and butyl ether can be used as solvents for the coatingcomposition. Mixtures of alcohols and aromatic hydrocarbons may bepreferred as solvents because of the high mutual solubility ofamino-aldehyde and alkyd resins therein. The choice of the solvent andthe amount used will depend on the coating method and drying equipmentused. Generally about 50 to 75% solvent (wet basis weight) may be used.

Any conventional coating technique can be used to apply the releasecoating composition to the substrate such as brushing, spreading,rolling, wire or knife coating, roll coating, gravure coating, transferroll coating, air knife or doctor blade coating. The coating can besuccessfully applied with direct gravure, reverse gravure, single ordouble Mayer rod, knife-over-roll, and inverted knife techniques. Thetechnique is selected for the substrate to be coated. The coatingviscosity is adjusted for the coating technique. The coating solids isadjusted to provide the requisite coating viscosity.

To any article or substrate on which the coating has been applied, driedand cured, an SPSA adhesive, which has been previously dried andcrosslinked, can be applied and easily removed. The release coating canbe applied to any suitable substrate. Some of the most common substratesare flexible films, papers, cloth, foils, glass and metal. Both crepedand uncreped papers may be used. Useful films include polyesters, e.g.,PET, polyolefins, polycarbonates and metallized films such as aluminizedpolyethylene-teraphthalate (PET).

The coat weight of the coating will vary depending upon many factorsincluding the nature of the substrate, for example, its absorbency,porosity, surface roughness, crepe, etc., whether the substrate is afilm or paper and whether the paper is impregnated. Generally, therelease coating is applied in an amount ranging from about 0.5 to 5pounds dry weight per 3,000 sq. ft. Film, foil, and super calendaredkraft substrates are typically coated with 35% solids material by director reverse gravure techniques to a dry coating weight of 0.5 to 1.5pounds per 3,000 sq. ft. ream. Coarse paper substrates, such as crepe orflatback, are typically coated with 35 to 45% solids material by any ofthe aforementioned techniques to a dry coat weight of 2 to 6 pounds per3,000 sq. ft. ream. While heavier coat weights may be used, this isgenerally economically undesirable. As previously mentioned, oneadvantage of the invention is that the release coat is economical foruse on rough or more highly absorbent substrates.

In some cases, it may be desirable to use a primer coat to enhance thebond between the release coat and the substrate such that the curedrelease coating bonds to the substrate with a force greater than theforce needed to remove the adhesive from the coating. For example, aprimer coat may be used to maximize the bond between the release layerand a film such as PET or a foil. On the other hand, the primer isoptional and the need for it will depend on the particular application.For example, while a primer is often used with non-matte PET, it isgenerally not required with matte PET.

A useful primer for PET may be prepared from a carboxyl terminatedbutadiene-acrylonitrile resin (CTBN) or an amine terminatedbutadiene-acrylonitrile (ATBN) resin, an aminoplast and, moreparticularly, butylated melamine formaldehyde resin and a catalyst suchas p-toluene sulfonic acid. The CTBN or ATBN are reacted in an amount ofabout 3 parts to 1 part of the aminoplast resin. The catalyst is presentin an amount of about 0.5 to 2%. Examples of CTBN or ATBN polymers arecommercially available from B. F. Goodrich under the trade names HYCAR1300X8, 1300X9, 1300X13, 1300X15, 1300X18 or 1300X31. Chlorinated orsulfonated maleic anhydride polymers such as DuPont's Hypalon CP-4281and CP-429 may be used instead of the CTBN or ATBN polymers. Theaminoplast may be CYMEL 303, 323, 373 or 350. The coating may be appliedfrom a 25% solids solution in toluene in a coat weight of 0.5 to 1.0pound per 3000 sq. ft. and dried and cured at 300° to 350° F. for about5 to 30 seconds immediately prior to application of the release coating.The coating is successfully applied with direct gravure, reverse gravuretechniques, and Mayer rod techniques.

Film and foil substrates are typically coated with the primer as a 25%solids solution material by direct or reverse gravure techniques to adry coating weight of 0.5 to 1.5 pounds per 3,000 sq. ft. ream. Thecoating is dried and cured, prior to the application of the releasecoating, in much the same fashion as the release coating.

One primer can be compounded as follows:

    ______________________________________                                        Material     Description   Dry %     Wet %                                    ______________________________________                                        Hycar 1300X8 Reactive liquid nitrile                                                                     74.0      18.5                                     Toluene                    --        70.8                                     Doresco BM8-1                                                                              butylated melamine                                                                          24.0       9.7                                     Doresco G-17 p-toluenesulfonic acid                                                                       2.0       1.0                                     ______________________________________                                    

Other primers may be used in the invention depending upon the substratein a manner well known in the art.

After applying the release coating composition to the substrate, thecoating is heated to cure the coating and remove any solvent. Typicallythe coating will be heated to a temperature of about 300° to 350° F. forabout 5-30 seconds to accomplish curing. Because of the low coatingweights involved, drying is easily achieved. The dried coating must thenbe cured to ensure that the film forming matrix is fully crosslinked andthat the perfluorinated side chains "bloom" to its surface. Atime/temperature relationship exists for curing the coating. The time ofthe cure is a function of the temperature that the coating achieves. Thetemperature used is selected for the substrate to which the coating isbeing applied. Heavier or thicker articles will require more time toachieve the desired temperature for curing. Typically 5 seconds at 350°F. achieves the desired level of crosslink density and blooming for thecoating.

The release coating composition of the invention can be used in any ofthe applications in which release coatings are typically appliedincluding a release liner or slip sheet for mill stocks, a release linerfor pressure-sensitive dye cuts, a processing aid for silicone rubber,etc.

In accordance with another embodiment of the invention, a self woundadhesive tape is provided. In this embodiment, the OPSA or SPSA may becoated on one side of a backing the opposite side of which carries therelease coating.

It is also anticipated that the invention may be useful in providing atransfer pressure sensitive adhesive. In this type of laminated articlethe laminate typically further comprises a second release layer that isin contact with the PSA, such as the next turn if the article has theform of a roll or a separate release backing if the article has the formof a sheet. The laminate possesses the property of differential releasewhereby one of the release layers is more easily released from the PSAthan the other release layer. Differing release forces are availablethrough the use of coating compositions having different release forces(e.g., by varying the amount of fluoropolymer). Additionally, differingrelease forces may be inherently available when the PSA is solvent-castonto one coated substrate and brought into adhesive contact with anothersubstrate, identically coated, after it has been freed of solvent and,optionally, cured. Of course, a combination of these two methods canalso be used to provide differential release.

The invention may also be useful in cases where the PSA is durablyadhered to an item that is to be ultimately adhered to a support.Examples thereof include, but are not limited to, medical items, such astransdermal drug delivery items and ostomy devices; trim items, such asdecorative emblems and protective strips that are applied to vehicles;and decals, such as instrument panel templates and labels. As notedabove, these articles can be prepared by applying the PSA to the releasebacking and thereafter durably adhering the item to the PSA, or viceversa.

The release coating of the present invention can be used in conjunctionwith any PSA including, but not limited to, conventional or commerciallyavailable OPSAs and SPSAs. References disclosing SPSAs have been citedpreviously. Reference can be made to the literature for examples ofthese compositions.

The invention is illustrated in more detail by the following nonlimitingexample:

EXAMPLE 1

    ______________________________________                                        Material     Description   Dry %     Wet %                                    ______________________________________                                        Hycar 1300x8 reactive liquid nitrile                                                                     74.00     25.88                                    Toluene                    --        59.18                                    Doresco BM8-1                                                                              butylated melamine                                                                          24.00     13.54                                    Doresco G-17 p-toluenesulfonic acid                                                                       2.00      1.40                                    ______________________________________                                    

Reactive liquid nitrile (25.88 parts) and toluene (59.18 parts) aremixed together in a suitable vessel until homogenous. To this mixture,13.54 parts of butylated melamine is added and mixed until the mixturebecomes homogenous again. While this mixture is being agitated, 1.40parts of p-toluenesulfonic acid is added. The resultant primer coatingexhibited a total solids of 35%.

Approximately two wet pounds per 3000 ft² ream of the primer coating isapplied to 2 mil PET film from a 200 QCH anilox roll using reversegravure technique. The coating is quickly dried and cured by processingit through a 350° F. flotation drier for 5 seconds. The resultant drycoating weight is measured to be 0.7 pounds per 3000 ft² ream.

    ______________________________________                                        Material    Description    Dry %   Wet %                                      ______________________________________                                        Doresco AKN29-1                                                                           short oil alkyd                                                                              68.08   47.70                                      Doresco BM8-1                                                                             butylated melamine                                                                           22.08   12.47                                      Zonyl 7040  perfluorinated ester                                                                          8.00   14.91                                      Doresco G-17                                                                              p-toluenesulfonic acid                                                                        1.84    1.29                                      Toluene                    --      24.53                                      ______________________________________                                    

Short oil alkyd (47.7 parts) and butylated melamine (12.47 parts) aremixed together in a suitable vessel until homogenous. To this mixture,14.01 parts of Zonyl 7040 is added and mixed until the mixture becomeshomogenous again. While this mixture is being agitated, 1.20 parts ofp-toluenesulfonic acid is added. Toluene (24.53 parts) is added so thatthe release coating exhibits a total solids of 35%.

Approximately two wet pounds per 3000 ft² ream of the release coating isdeposited on the dried and cured primer coating from a 200 QCH aniloxroll using direct gravure technique. The coating is quickly dried andcured by processing it through a 350° F. flotation drier for 5 seconds.The resultant dry coating weight is measured to be 0.7 pounds per 3000ft² ream.

The release coating is measured for any tendency to detackify an SPSA byplacing a 1/2 " strip of any commercially available SPSA tape onto therelease surface. The strip of tape is then rolled down, once eachdirection, with a 10 pound, rubber coated roller at a speed of 12" perminute. The SPSA tape is then carefully "popped" so as not to fractureit, and placed onto a stainless steel panel. A virgin (control) strip ofthe SPSA tape is then placed on the same stainless steel panel alongside the tape which was exposed to the release surface. Both strips oftape are rolled down, once in each direction, with a 41/2 pound, rubbercoated roller at a speed of 12" per minute. A panel adhesion is measuredon each strip of tape and the values compared. If the adhesion value ofthe control tape exceeds the adhesion value of the tape exposed to therelease surface by more than 5% then detackification is suspected. Nosigns of detackification were observed.

To the side of the PET film opposite the primer and the release coating,85 wet pounds per 3000 ft² ream of the

    ______________________________________                                        Material  Description      Dry %   Wet %                                      ______________________________________                                        PSA 590   polydimethylsiloxane PSA                                                                       98.0%   65.46                                      Toluene                    --      33.74                                      Lucidol 98                                                                              benzoyl peroxide 2.0      0.80                                      ______________________________________                                    

The adhesive was dried at 190° F. for 2 minutes and cured at 330° F. for2 minutes resulting in a dry coating weight of 34 pounds per 3000 ft²ream.

The coated tape was slit into one inch widths and wound on 3" cores. Thefinished tape exhibited the following properties. All properties weremeasured at 72° F. and 50% r.h. except where noted.

    ______________________________________                                        Property                oz/inch                                               ______________________________________                                        panel adhesion to stainless steel                                                                     45.4                                                  quick stick to stainless steel                                                                        20.2                                                  high speed unwind @ 50 fpm                                                                             4.2                                                  initial adhesion to release                                                                            2.0                                                  adhesion to release after 24 hours                                                                     9.0                                                  adhesion to release after 1 week                                                                       5.0                                                  adhesion to release after 24 hours @ 70 C.                                                            18.0                                                  adhesion to release after 1 week @ 70 C.                                                              16.0                                                  ______________________________________                                    

EXAMPLE 2

Approximately 16.5 wet pounds per 3000 ft² ream of the release coatingfrom Example 1 is deposited on the felt side of a 45 pound, SBRsaturated, fine structured crepe backing by applying it with a smoothapplicator roll and doctoring it from the substrate with a #18 and #9dual Mayer rod set-up. The coating is quickly dried and cured byprocessing it through a 350° F. flotation drier for 5 seconds. Theresultant dry coating weight is measured to be 5.8 pounds per 3000 ft²ream.

The finished tape from Example 1 was applied to the release coated SCK.The following properties were measured:

    ______________________________________                                        Property                oz/inch                                               ______________________________________                                        initial adhesion to release                                                                           1.0                                                   adhesion to release after 24 hours                                                                    2.0                                                   adhesion to release after 1 week                                                                      2.5                                                   adhesion to release after 24 hours @ 70 C.                                                            5.5                                                   adhesion to release after 1 week @ 70 C.                                                              5.5                                                   ______________________________________                                    

To the wire side of the crepe backing, the side opposite the releasecoating, 85 wet pounds per 3000 ft² ream of the following SPSA was cast:

    ______________________________________                                        Material Description       Dry %   Wet %                                      ______________________________________                                        Dow 282  polydimethylsiloxane PSA                                                                        98.0    70.00                                      Toluene                    --      29.20                                      Cadox TS-50                                                                            2,4-dichlorobenzoyl peroxide                                                                     2.0     0.80                                      ______________________________________                                    

The adhesive was dried at 190° F. for 2 minutes and cured at 350° F. for1 minute resulting in a dry coating weight of 34 pounds per 3000 ft²ream.

The coated tape was slit into one inch widths and wound on 3" cores. Thefinished tape exhibited the following properties. All properties weremeasured at 72° F. and 50%.

    ______________________________________                                        Property            oz/inch                                                   ______________________________________                                        panel adhesion to stainless steel                                                                 31.2                                                      quick stick to stainless steel                                                                    7.7                                                       high speed unwind @ 50 fpm                                                                        5.0                                                       ______________________________________                                    

EXAMPLE 3

Approximately two wet pounds per 3000 ft² ream of the release coating inExample 1 is applied to the felt side of 3.2 mil super calendered kraft(SCK) from a 200 QCH anilox roll using reverse gravure technique. Thecoating is quickly dried and cured by processing it through a 350° F.flotation drier for 5 seconds. The resultant dry coating weight ismeasured to be 0.7 pounds per 3000 ft² ream.

The finished tape from Example 1 was applied to the release coated SCK.The following properties were measured:

    ______________________________________                                        Property             oz/inch                                                  ______________________________________                                        initial adhesion to release                                                                        1.5                                                      adhesion to release after 24 hours                                                                 8.0                                                      adhesion to release after 1 week                                                                   13.5                                                     ______________________________________                                    

Having described the invention in detail and by reference to preferredembodiments thereof, it will be apparent that modifications andvariations are possible without departing from the scope of theinvention defined in the appended claims.

What is claimed is:
 1. A laminate comprising a substrate, a continuouslayer of a release coating on one surface thereof, and a layer of asilicone pressure sensitive adhesive on the surface of said releasecoating, said release coating being a mixture of a resin havingperfluoro side chains and a film forming resin which binds said resinhaving said perfluoro side chains to said substrate, wherein said filmforming resin is selected from the group consisting of polyester,polyamides, functionalized polyolefins, and nitrile polymers andcopolymers.
 2. The laminate of claim 1 wherein said film forming resinis a polyester.
 3. The laminate of claim 2 wherein said film formingresin is the reaction product of an alkyd resin and an aminoplast resin.4. The laminate of claim 3 wherein said resin having perfluoro sidechains is a polymer of a perfluoroalkyalkyl acrylate or methacrylate. 5.The laminate of claim 4 wherein said aminoplast resin is butylatedmelamine formaldehyde resin.
 6. The laminate of claim 5 wherein saidperfluoropolymer is present in said composition in an amount of about 2to 10% by dry weight, said alkyd resin is present in an amount of about40 to 90% by dry weight, and said aminoplast resin is present in anamount of about 10 to 50% by dry weight.
 7. A backing for a siliconepressure sensitive tape or a silicon pressure sensitive adhesive releaseliner comprising a substrate having a continuous release coating on asurface thereof comprising a cured composition of a mixture of a resinhaving perfluoro side chains, a polyester resin and an aminoplast resin.8. The backing of claim 7 wherein said polyester resin is an alkydresin.
 9. The backing of claim 8 wherein said resin having perfluoroside chains is a polymer of a perfluoroalkylalkyl acrylate ormethacrylate ester.
 10. The backing of claim 9 wherein said alkyd resinis a coconut oil alkyd resin.
 11. The backing of claim 10 wherein saidaminoplast is butylated melamine formaldehyde resin.
 12. The backing ofclaim 11 wherein said perfluoropolymer is present in said composition inan amount of about 2 to 10% by dry weight, said alkyd resin is presentin an amount of about 40 to 90% by dry weight, and said aminoplast resinis present in an amount of about 10 to 50% by dry weight.
 13. Thebacking of claim 12 wherein said substrate is apolyethyleneterephthalate film and a primer layer is interposed betweensaid coating and said substrate.
 14. The backing of claim 13 whereinsaid primer coating is a cured composition of an amine or carboxylterminated butadiene-acrylonitrile resin and an aminoplast resin.
 15. Apressure-sensitive adhesive tape comprising a flexible substrate havinga first surface and a second surface, said first surface having acontinuous layer of a release coating thereon and said second surfacehaving a layer of a silicone pressure-sensitive adhesive thereof, saidrelease coating being a cured composition of a film forming resin and aresin having perfluoro side chains wherein said film forming resin isselected from the group consisting of polyester, polyamides,functionalized polyolefins, and nitrile polymers and copolymers.
 16. Thetape of claim 15 wherein said film forming resin is a polyester.
 17. Thetape of claim 16 wherein said film forming resin is the reaction productof an alkyd resin, an aminoplast resin and a curing agent.
 18. The tapeof claim 17 wherein said resin having perfluoro side chains is a polymerof a perfluoroalkyalkyl acrylate or methacrylate.
 19. The tape of claim18 wherein said alkyd resin is a coconut oil alkyd resin.
 20. The tapeof claim 19 wherein said aminoplast resin is butylated malamineformaldehyde resin.
 21. The tape of claim 20 wherein saidperfluoropolymer is present in said composition in an amount of about 2to 10% by dry weight, said alkyd resin is present in an amount of about40 to 90% by dry weight, and said aminoplast resin is present in anamount of about 10 to 50% by dry weight.
 22. The tape of claim 15wherein said silicone pressure sensitive adhesive contains a resinhaving perfluoro side chains.
 23. The tape of claim 15 wherein saidsubstrate is a polyethyleneterephthalate film and a primer layer isinterposed between said coating and said substrate.
 24. The tape ofclaim 23 wherein said primer coating is a cured composition of an amineor carboxyl terminated butadiene-acrylonitrile resin and an aminoplastresin.